• retagged by
1,286 views

1 Answer

Best answer
15 15 votes

Let

$L_1=\{a^p \; \mid \; \text{p is prime}\}$, and $L_2=\{a^nb^m \; \mid \; m,n\geq 0\}$

then  $L_1.L_2=\{a^ib^j \; \mid \; i\geq 2,j\geq 0\}$ is Regular.

and $L_2.L_1=\{a^ib^ja^p \; \mid \; i,j\geq 0,\text{p is prime}\}$ is Non-regular.

So both statement are false. 

• selected by
Position:
Show:

Related questions

1 1 vote
1 1 answer
59
59 views
GO Classes asked 5 days ago
59 views
Let $M$ and $N$ be two DFAs. Define$$Z=\{u_1v_1u_2v_2\cdots u_kv_k : k\ge0, ~u_i\in L(M), ~v_i\in L(N)\}.$$Which regular-language expression describes $Z$?$L(M)^*L(N)^*$ ...
0 0 votes
1 1 answer
50
50 views
GO Classes asked 5 days ago
50 views
For an arbitrary language $L$, which of the following statements is correct?If $L^*$ is regular, then $L$ must be regular. If $L$ is nonregular, then $L^*$ must be nonreg...
1 1 vote
1 1 answer
71
71 views
GO Classes asked Sep 16
71 views
Let $L=\{w\in{0,1}^*\mid w$ contains equal numbers of substrings $01$ and $10\}$. Which statements are correct?$L$ is regular. A correct regular expression for $L$ is $\e...
1 1 vote
1 1 answer
59
59 views
GO Classes asked Sep 16
59 views
Let $L_n=\{0^n1^n\}$ for each $n\ge0$. Which statements are correct?Each $L_n$ is regular. Any finite union of such languages is regular. $\bigcup_{n\ge0}L_n=\{0^n1^n\mid...